The present invention relates to a wrench with maximum operational torque and, more particularly, to a wrench having maximum operational torque and allowing switching between two operational modes.
U.S. Pat. No. 7,281,457 discloses a wrench with adjustable maximum operational torque. In actual use, when a screw is gradually tightened but the rotational force has not reached the predetermined torque value of the wrench, the user would find that the rotational force applied by his or her fingers can not be increased and, thus, can not further tighten the screw. As a result, the screw can not be tightened to the desired preset extent.
To solve the above problem, the user generally tries to hold the wrench with the whole palm for the purposes of increasing the rotational force. However, the cylindrical protrusion on the top of the wrench hinders transmission of the rotational force to the wrench, leading to loss in the rotational force created by the wriest and the palm of the user and even causing pain or discomfort to the palm of the user. Thus, the user often rotates the wrench with both hands to achieve the desired preset tightening extent. However, operation of both hands is inconvenient to the user, reducing the purchase desire of the consumers and adversely affecting the reputation of this product.
Thus, a need exists for a novel wrench with maximum operational torque to mitigate and/or obviate the above disadvantages.